Electrical switching device having self-cleaning contactor elements

ABSTRACT

An electrical switching device which is capable of effecting continuous self-cleaning of its contactor elements, each time it is operated, includes a plurality of arcuate contactor elements and respective opposed linear contactor elements, for accomplishing make, break and transfer switching functions. The arcuate contactor elements are mounted on a carrier member and have a first preselected radius. In effecting a switching operation, the carrier member is moved linearly and is simultaneously rotated about a second preselected radius which is different from the first preselected radius, to cause simultaneous rotation and sliding movement of the arcuate contactor elements relative to the linear contactor elements, thereby to effect a continuous controlled wiping and cleaning action between the contactor elements, and thus the establishment of good electrical contact therebetween. Either the arcuate contactor elements or the linear contactor elements may be independently resilient in nature.

United States Patent 1191 Brandlein Dec. 31, 1974 [75] Inventor: JamesD. Brandlein, Indianapolis,

Ind.

[73] Assignee: Western Electric Company,

Incorporated, New York, NY.

FOREIGN PATENTS OR APPLICATIONS 956,565 4/1964 Great Britain 200/ 1641,093,067 11/1967 Great Britain 200/164 Primary Examiner-G. HarrisAttorney, Agent, or FirmD. D. Bosben [57] ABSTRACT An electricalswitching device which is capable of effecting continuous self-cleaningof its contactor elements, each time it is operated, includes aplurality of arcuate contactor elements and respective opposed linearcontactor elements, for accomplishing make, break and transfer switchingfunctions. The arcuate contactor elements are mounted on a carriermember and have a first preselected radius. In effecting a switchingoperation, the carrier member is moved linearly and is simultaneouslyrotated about a second preselected radius which is different from thefirst preselected radius, to cause simultaneous rotation and slidingmovement of the arcuate contactor elements relative to the linearcontactor elements, thereby to effect a continuous controlled wiping andcleaning action between the contactor elements, and thus theestablishment of good electrical contact therebetweenv Either thearcuate contactor elements or the linear contactor elements may beindependently resilient in nature.

10 Claims, 11 Drawing Figures ELECTRICAL SWITCHING DEVICE HAVINGSELF-CLEANING CONTACTOR ELEMENTS BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to a contact making device havingself-cleaning contactor elements, and more particularly to an electricalswitching device capable of reliably effecting make, break or transferswitching functions as a result of opposed electrical contactor elementsof the switch producing a continuous sliding and cleaning actionrelative to one another as the switch is moved between its differentoperating positions.

2. Description of the Prior Art A frequent problem in the manufacture ofelectrical devices which are to be capable of effecting switchingfunctions, is the inability to establish good electrical contact betweencontactor elements of the device as the result of dirt and/or oxideformations on the surfaces of the contactor elements. The dirt and oxideformations function as insulators and increase the resistance betweenthe contact surfaces so as to prevent their associated electricalcircuits from closing, or at least from performing properly. This isparticularly true in electronic circuits which are designed to operateat a relatively low power level.

Roller-type contact members which are engageable and disengageable withassociated contact members or elements for effecting switching functionsare undesirable because of the accumulation of dirt and oxide formationson the contact surfaces, as discussed hereinabove. Further, the use ofsliding-bar contact members to provide a cleaning action between the barcontact members and associated linear contact members, isdisadvantageous because of the excessive wear between the contactmembers, and is particularly undesirable in instances where the contactmembers are of relatively thin material. Similarly, in the British pat.No. 1,093,067, issued Nov. 29, 1967, as a roller-type contact member ismoved between its operating positions, it initially rolls during a firstportion of its movement, and then the rolling movement of the contactmember is interrupted so that it slides on associated linear contactmembers during the latter portion of its movement. As in the case of thesliding-bar contact members, however, this arrangement will produceexcessive wear on the contact members.

SUMMARY OF THE INVENTION In accordance with this invention, a contactmaking device includes an arcuate contactor element for making contactwith a substantially linear contactor element. In operation, a lineartranslating motion and a rotary motion are simultaneously imparted tothe arcuate contactor element, to rotate and slide the arcuate contactorelement simultaneously and continuously on the linear contactor element,to effect contact between the contactor elements while cleaning thecontactor elements.

More specifically, in an electrical switching device a plurality ofarcuate contactor elements are mounted on a carrier member and have afirst preselected radius. In effecting a switching operation, thecarrier member is moved linearly and is simultaneously rotated about asecond preselected radius which is different from the radius of thearcuate contactor elements, to cause simultaneous rotation and slidingmovement of the arcuate contactor elements on respective opposed linearcontactor elements, thereby effecting cleaning of the contactor elementsand the establishment of good electrical contact therebeetween.Establishment of good electrical contact between the contactor elementsalso is facilitated by making at least one of each of the opposedcontactor elements independently resilient in nature.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top view of an electricalswitching device in accordance with the invention, partially incrosssection. with the device shown in a position intermediate first andsecond operating positions thereof;

FIG. 2 is a cross-sectional view taken along the line 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view of the electrical switching deviceshown in FIG. 1 taken along the line 3-3 and showing the first andsecond operating positions of the device;

FIG. 4 is a cross-sectional view taken along the line 4-4 in FIG. 1,with the switching device in its first operating position;

FIG. 5 is a plan view as seen along the line 5-5 in FIG. 2;

FIG. 6 is a schematic view illustrating a principle of the invention;

FIG. 7 is a schematic view similar to FIG. 6 and further illustratingthe principle of the invention;

FIG. 8 is a plan view of an alternate embodiment of an electricalswitching device in accordance with the invention, with the device shownin a position intermediate first and second operating positions thereof;

FIG. 9 is a partial cross-sectional view as seen along the line 9-9 inFIG. 8;

FIG. 10 is an elevational view showing first and second operatingpositions of the switching device in FIG.

FIG. 11 is another alternate embodiment of the invention similar to theembodiment of the invention shown in FIGS. 8, 9 and 10.

DETAILED DESCRIPTION FIGS. l6 illustrate a self-cleaning electricalswitching device 16 having a contactor assembly 17 capable of effectingmake, break and transfer switching functions when it is moved between afirst operating position as shown in solid lines in FIG. 3, and a secondoperating position as shown in broken lines in this figure. Theswitching device 16 also includes a bottom wall in the form of a printedcircuit board 18, and a plastic housing I9 which forms top and sidewalls for the device and which is molded as an integral unit. Theprinted circuit board 18 is suitably secured to the plastic housing 19,such as by screws.

As is best shown in FIG. 5, a top surface 18a of the printed circuitboard 18 has a pair of linear mal e" the transfer contactors 23-1 and23-2 extend from adjacent respective opposite sides of the printedcircuit board 18 to approximately the center thereof, while the transfercontactor 23-3 extends on opposite sides of the center of the board soas to be capable of completing an electrical circuit with one or theother of the transfer contactors 23-1 and 23-2 through the movablecontactor assembly 17 when it is in respective ones of its operatingpositions. Respective leads 24 extend through the bottom of the printedcircuit board 18 and are electrically connected to the contactors 21, 22and 23 in a suitable manner, such as by soldering.

The movable contactor assembly 17 includes a carrier member 26 of asuitable insulating material, such as plastic, and which has flanges 26aat each end thereof. Mounted on the carrier member 26 is a makeelectrical contactor 27, a break electrical contactor 28 and a transferelectrical contactor 29. When the carrier member 26 is in its solid lineposition, its make contactor 27 is disengaged from the linear makecontactor elements 21 on the printed circuit board 18, its breakcontactor 28 is engaged with the linear break contactor elements 22 tocomplete a circuit therethrough, and its transfer contactor 29 isengaged with the linear transfer contactor element 23-1 and therelatively long transfer contactor element 23-3, to establish anelectrical circuit therebetween. When the carrier member 26 is movedinto its position as shown in broken lines in FIG. 3, its make contactor27 engages the linear make contactor elements 21, its break contactor 28disengages from the linear break contactor elements 22, and its transfercontactor 29 disengages from the linear transfer contactor element 23-1and engages with the linear transfer contactor element 23-2, whileremaining in contact with the relatively long transfer contactor element23-3, thus performing a make, break and transfer switching function.

The make, break and transfer contactors 27, 28 and 29 effect theircorresponding switching functions with the linear contactor elements 21,22 and 23 on the printed circuit board 18 as the result of arcuatecontactor elements 27a, 28a and 29a of the contactors rocking orrotating between the positions shown in FIG. 3, while simultaneously andcontinuously sliding relative to the linear contactor elements with awiping action at a controlled rate, to effect self-cleaning of both setsof the contactor elements. In the embodiment of the invention shown inFIGS. l6, this is accomplished by constructing the arcuate contactorelements 27a, 28a and 29a with a first radius R, (FIG. 6), and providingthe flanges 26a of the carrier member 26 with arcuate segments having aslightly larger radius R the difference between the two radii beingexaggerated in the figures for the purpose of illustration. The arcuatesegments of the flanges 26a ride on bottom surfaces 18b of recesses inthe top surface 18a of the printed circuit board 18, the top surface 18aand the bottom surfaces 18b being offset a distance equal to, orslightly less than, the difference between the radii R and R The flanges2611 also include gear teeth 26b which are receivable in apertures inthe bottom surfaces 18b, with portions 180 of the board 18 adjacent theapertures defining a gear rack for the teeth. Thus, as a lineartranslating motion is imparted to the carrier member 26 by a plunger 31,the teeth 26b and the board portions 180 react with one another to causea controlled rocking or rotating of the carrier member about the radiusR while the arcuate contactor elements 27a, 28a and 29a rock or rotateabout the radius R,. Further, since the flanges 26a and the arcuatecontactor elements 27a, 28a and 29a must move together, the arcuatecontactor elements also continuously slide relative to the linearcontactor elements 21, 22 and 23, as is illustrated in FIG. 6.

More specifically, in FIG. 6 the carrier member 26 is depicted as asemi-circular rocker member having a hub portion of the relatively smallradius R, and corresponding to the arcuate contactor elements 270, 28aand 29a, and having toothed arcuate flanges of the relatively largeradius R and corresponding to the flanges 26a. The toothed flanges 26arock or rotate on an apertured planar surface corresponding to thebottom surfaces 18b of the recesses in the printed circuit board 18, andthe hub portion 27a, 28a and 29a rocks or rotates on a planar surfacecomparable to the top surface 18a of the printed circuit board 18 andthe electrical contactor elements 21, 22 and 23. Thus, as the rockermember 26 rocks or rotates clockwise 60, from the solid line position tothe broken line position in FIG. 6, it is seen that a point 26p-l on theinner periphery of each of the toothed flanges 26a will move to aposition 2612-2 on the surface 1812. Similarly, if the hub portion 27a,28a, 290 could be rotated independently of the flanges 26a through thesame are, a point 27p-l on the periphery of the hub portion and on thesame radius line as the point 26p-l, would move a lesser distance to aposition 27p-2 on the surface 18a, 21, 22, 23. However, since the hubportion 27a, 28a, 29a must rotate with the flanges 26a, the point 27p-lactually moves to a position 27p-3 on the surface 18a, 21, 22, 23, withthe difference X between the position 27p-2 and 27p-3 representing thedistance which the periphery of the hub portion must continuously slideon the surface during the rotation of the rocker member 26 so as toarrive ultimately at the position 27p-3. Thus, it is apparent that byproperly varying the two radii R, and R a desired controlled cleaningaction between the contactor elements 21, 22, 23, 27a, 28a, and 29a canbe achieved without producing excessive wear therebetween.

FIG. 7 is similar to FIG. 6 except that a radius R, of a hub portion27a, 28a, 29a on a rocker member 26 is relatively large, whereas aradius R of toothed flanged 26a of the rocker member is relativelysmall. In this illustration, as the flanges 26a are rocked or rotatedclockwise 60 on a planar surface 18b, a point 26p-1 on each flange 26awill move to a position 26p- 2' on the surface. While a point 27p-1' onthe periphery of the hub portion 27a, 28a, 29a and on the same radiusline as the point 26p-l' would have moved forward to a position 27p-2 ona planar surface 18a, 21 22, 23, if the hub portion were free to rotateon the surface independently of the flanges 26a, the point 27p-1actually moves only to a position 27p-3' on the surface 18a, 21', 22',23. The difference X between the positions 27p-2 and 27p-3' againrepresents the distance which the hub portion 270', 28a, 29a must sliderelative to the surface 18a, 21', 22', 23', but in this instance in areverse direction as compared to that of the hub portion 27a, 28a, 29ain FIG. 6. As in FIG. 6, the degree of sliding movement of the hubportion 27a, 28a, 29a is determined by the difference between the radiiR, and R As is best shown in FIGS. 1 and 2, the arcuate contactorelements 27a, 28a and 29a (FIG. 2) are formed in pairs for engagementwith respective ones of the linear contactors 21, 22 and 23, and areintegral with respective diametrical portions 27b,.28b and 29b (FIG. 1)and mounting portions 27c, 28c, and 29c of the contractors 27, 28 and29.The mounting portions 270, 28c and 29c of each of the contactors 27, 28and 29 are disposed in opposed relationship through a respective slot260 in the carrier member 26, and are held secured in the slot by theinherent resiliency of the contactors and a pair of suitable retainingdimples formed in the mounting portions. The arcuate contactor elements27a, 28a and 29a also are independently resilient to assure goodelectrical contact with their respective linear contactors 21, 22 and 23despite irregularities in the top surface 18a of the printed circuitboard 18. In this regard, the arcuate contactor elements 27a, 28a and29a are maintained in firm pressure engagement with the linearcontactors 21, 22 and 23 by pressure rollers 32 mounted on projectingshaft portions of the carrier member 26 at each end thereof. Thepressure rollers 32 are engaged with the adjacent side walls of theplastic housing 19 to preclude longitudinal movement of the carriermember 26, and the peripheral surfaces of the rollers ride on the innersurface of the top wall of the housing.

FIGS. 8-l0 disclose an alternate embodiment of the invention in which anelectrical switching device 16" includes a mounting board 18" of aninsulating material, such as plastic, having a pair of make contactorelements 21", a pair of break contactor elements 22" and a set oftransfer contactor elements 23-1", 23-2" and 23-3, on a top surface 18athereof. The make and break contactor elements 21" and 22 are fixed to acentral portion of the mounting board 18" by having inner end portionsthereof extended through the board and soldered to respective leads 24".The transfer contactor elements 23-1" and 23-2" are fixed to the centralportion of the mounting board 18" in the same manner, while the transfercontactor element 23-3 extends across the board and has an intermediateportion projected through and fixed to the board centrally thereof. Thecontactor elements 121, 22 and 23 are resilient and essentially linearin configuration, except that outer end portions thereof extend upwardrelative to the mounting board 18" as illustrated in FIG. 9, tofacilitate the establishing of electrical contact therewith despiteirregularities in the top surface 18a" of the mounting board.

The electrical switching device 16" also includes a carrier member 26"of an insulating material, such as plastic, and having a semi-circularconfiguration. A make contactor 27", a break contactor 28" and atransfer contactor 29" are mounted on the carrier member 26" withintermediate portions of the contactors formed about an arcuate surfacethereof on a radius R to provide arcuate contactor elements 27a", 28a"and 29a", with diametrical portions 27b", 28b and 29b ofthe contactorsfolded into overlapped relationship and secured to the carrier member bysuitable screws. The arcuate contactor elements 27a", 28a" and 29a" alsomay be made independently resilient in nature, as in the embodiment ofFIGS. 1-6, if so desired.

Adjacent the opposite ends of the carrier member 26" laterallyprojecting flanges or legs 26a thereof have inwardly directed mountinglugs 26b" disposed between opposed parallel surfaces 18c" (FIG. 9) ofrespective recesses in the mounting board 18'. so that the carriermember is capable of pivotal movement on, and linear movementperpendicular to. the top surface .1812" of the board. As is best shownin FIG. 9, an elongated wire spring 37 is disposed in a longitudinallyextending slot in the mounting board 18" between each mounting lug 26b"and an enlarged concave portion of the slot, to permit the carriermember to be rotated about the lugs on a radius R Thus. as the carriermember 26" is rotated between its operating positions as shown in solidand broken lines in FIG. 10, the wire springs 37 hold the carriermember. and thus the arcuate contactor elements 27a", 28a and 29a", infirm engagement with the mounting board 18" and/or the linear contactorelements 21" 22" and 23". As a result, the arcuate contactor elements27a", 28a and 29a" move relative to their respective linear contactorelements 21", 22" and 23" on the mounting board 18" to perform theirrespective switching functions with a combined rotating and slidingaction, thereby effecting self-cleaning of both sets of the contactorelements each time the switching device 16 is operated. To facilitaterotation of the carrier member 26 between its two operating positions,an operating lever 39 is provided on one ofthe legs 26a" ofthe carriermember, as illustrated in FIG. 10.

FIG. 11 is an alternate embodiment of the invention of the same generalconstruction as the embodiment shown in FIGS. 8, 9 and 10, except thatthe biasing arrangement comprising the wire springs 37 is replaced withclip-type spring 41. In this embodiment, each leg 2611" of a carriermember 26'" is provided with an outwardly projecting lug 42 and a lostmotion slot for receiving a laterally projecting pin 43 fixed to amounting board 18". The spring clip 41 is engaged over the outwardlyprojecting lug 42 and the projecting pin 43 to retain arcuate contactorelements 27a, 28a and 29a' on the carrier member 26 in engagement withthe mounting board 18 and/or respective linear contactor elements 21",22 and 23" on the mounting board. In other respects, the operation ofthe embodiment shown in FIG. 11 is substantially identical to theoperation of the embodiment of FIGS. 8, 9 and 10.

Summarizing, in embodiments of the invention as illustrated in FIGS.1-7, and referring to FIGS. l-6 for the purpose of illustration, it isseen that an electrical switching device 16 has been disclosed in whichthe arcuate contactor elements 27a, 28a and 29a continuously sliderelative to the linear contactor elements 21, 22 and 23 on the printedcircuit board 18 with a wiping action at a controlled rate as the deviceis moved between its different operating positions, to effect a cleaningaction on both sets of the contactor elements and thereby to insure goodelectrical contact therebetween. More specifically, the sliding movementof the arcuate contactor elements 270, 28a and 29a is achieved byrotating the carrier member 26 as a linear translating motion isimparted thereto, to cause simultaneous rotation and sliding movement ofthe arcuate contactor elements, with the degree of sliding and cleaningaction being dependent upon the difference between the radius ofrotation R of the arcuate contactor elements and the radius of rotationR of the carrier member. As a result, a desired cleaning action can beeffected without producing excessive wear of the contactor elements 21,22 and 23 on the printed circuit board, which is particularly importantwhere these contactor elements are of relatively thin material. Theindependently resilient arcuate contactor elements 27a, 28a and 29a alsohelp insure good electrical contact with their respective linearcontactor elements 21, 22 and 23 on the printed circuit board 18,despite irregularities in the top surface 18a of the board. Similarly,in embodiments of the invention as shown in FIGS. 8-11, and referringspecifically to FIGS. 8, 9 and 10, the desired controlled cleaningaction is achieved by properly varying the differential between theradius R," of the arcuate contactor elements 27a", 28a", 29a" and theradius of rotation R of the carrier member 26".

What is claimed is: l. A contact making device, which comprises: asubstantially linear contactor element mounted in a substantially fixedposition;

an arcuate movable contactor element mounted in coplanar relationshipwith respect to said linear contactor element, for engaging and makingcontact with said linear contactor element; and

means for rotating said arcuate contactor element while imparting atranslating motion to said arcuate contactor element, to rotate andslide said arcuate contactor element simultaneously and continuously onsaid linear contactor element, to effect contact between said contactorelements while cleaning said contactor elements. 2. A contact makingdevice, which comprises: a substantially linear contactor element: acarrier member: an arcuate contactor element mounted on said carriermember and having a first preselected radius;

means for imparting a translating motion to said carrier member and saidarcuate contactor element; and

means for causing rotation of said carrier member about a secondpreselected radius which is different from the first preselected radiusof said arcuate contactor element, during the translating movement ofsaid carrier member and said arcuate contactor element, to causesimultaneous rotation and sliding movement of said arcuate contactorelement on said linear contactor element.

3. A contact making device, as recited in claim 2, with furthercomprises:

means for biasing said arcuate contactor element and said linearcontactor element into engagement with one another during thetranslating and rotary movement of said carrier member.

4. A contact making device, as recited in claim 2, wherein the device isan electrical switching device and which further comprises:

a plurality of linear contactor elements; and

a plurality of arcuate contactor elements on said carrier member inopposed relationship to respective ones of said linear contactorelements for engagement therewith, said respective contactor elementsforming sets in which at least one of said contactor elements of eachset is resilient.

5. A contact making device as recited in claim 2, in

which:

the radius of said arcuate contactor element is less than the radius ofrotation of said carrier member.

6. A contact making device as recited in claim 2, in

which:

the radius of said arcuate contactor element is greater than the radiusof rotation of said carrier member.

7. A contact making device, as recited in claim 2,

which further comprises:

a support member having a planar surface portion on which said linearcontactor element is mounted;

reaction surface means offset with respect to the planar surface portionof said support member;

a flange on said carrier member, said flange having an arcuateperipheral segment of the second preselected radius and drivinglyengaged with said offset surface reaction means to cause the rotation ofsaid carrier member and the simultaneous and continuous rotation andsliding of said arcuate contactor element on said linear contactorelement when the translating motion is imparted to said carrier memberby said motion imparting means.

8. A contact making device, as recited in claim 7, in

which:

said offset reaction surface means is constructed in the form of a gearrack; and

the peripheral segment of said flange on said carrier member has teethreceivable in the gear rack formed by said reaction surface means.

9. A contact making device, as recited in claim 2,

which further comprises:

a support member having a planar surface portion on which said linearcontactor element is mounted;

means for mounting said carrier member on said sup port member forrotary movement about the second preselected radius and for linearmovement perpendicular to the planar surface portion of said supportmember;

means for rotating said carrier member about the second preselectedradius to move said carrier member relative to the planar surfaceportion of said support member; and

resilient means for causing linear movement of said carrier memberperpendicular to the planar surface portion of said support memberduring the rotational movement of said carrier member, so that saidarcuate contactor element simultaneously and continuously rotates andslides on said linear contactor element.

10. A contact making device, as recited in claim 9,

in which:

said linear contactor element is resilient and has at least one free endportion projecting from the planar surface portion of said supportmember for engagement by said arcuate contactor element.

UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTIQN Patent No. 858Dated December '31 107A lnventor(s) J. Do Brandlein It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

mlumn 2, line 4, "therebeetween" should read -therebetWeen--. I Column4, line 46, "flanged" should read "flanges-w Column 4, line 57, "X"should read -X'-. Column 6, line 31, before "clip-type", "a" should beinserted.

Signed and Scaled this twenty-second Day Of July 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parentsand Trademarks

1. A contact making device, which comprises: a substantially linearcontactor element mounted in a substantially fixed position; an arcuatemovable contactor element mounted in coplanar relationship with respectto said linear contactor element, for engaging and making contact withsaid linear contactor element; and means for rotating said arcuatecontactor element while imparting a translating motion to said arcuatecontactor element, to rotate and slide said arcuate contactor elementsimultaneously and continuously on said linear contactor element, toeffect contact between said contactor elements while cleaning saidcontactor elements.
 2. A contact making device, which comprises: asubstantially linear contactor element: a carrier member: an arcuatecontactor element mounted on said carrier member and having a firstpreselected radius; means for imparting a translating motion to saidcarrier member and said arcuate contactor element; and means for causingrotation of said carrier member about a second preselected radius whichis different from the first preselected radius of said arcuate contactorelement, during the translating movement of said carrier member and saidarcuate contactor element, to cause simultaneous rotation and slidingmovement of said arcuate contactor element on said linear contactorelement.
 3. A contact making device, as recited in claim 2, with furthercomprises: means for biasing said arcuate contactor element and saidlinear contactor element into engagement with one another during thetranslating and rotary movement of said carrier member.
 4. A contactmaking device, as recited in claim 2, wherein the device is anelectrical switching device and which further comprises: a plurality oflinear contactor elements; and a plurality of arcuate contactor elementson said carrier member in opposed relationship to respective ones ofsaid linear contactor elements for engagement therewith, said respectivecontactor elements forming sets in which at least one of said contactorelements of each set is resilient.
 5. A contact making device as recitedin claim 2, in which: the radius of said arcuate contactor element isless than the radius of rotation of said carrier member.
 6. A contactmaking device as recited in claim 2, in which: the radius of saidarcuate contactor element is greater than the radius of rotation of saidcarrier member.
 7. A contact making device, as recited in claim 2, whichfurther comprises: a support member having a planar surface portion onwhich said linear contactor element is mounted; reaction surface meansoffset with respect to the planar surface portion of said supportmember; a flange on said carrier member, said flange having an arcuateperipheral segment of the second preselected radius and drivinglyengaged with said offset surface reaction means to cause the rotation ofsaid carrier member and the simultaneous and continuous rotation andsliding of said arcuate contactor element on said linear contactorelement when the translating motion is imparted to said carrier memberby said motion imparting means.
 8. A contact making device, as recitedin claim 7, in which: said offset reaction surface means is constructedin the form of a gear rack; and the peripheral segment of said flange onsaid carrier member has teeth receivable in the gear rack formed by saidreaction surface means.
 9. A contact making device, as recited in claim2, which further comprises: a support member having a planar surfaceportion on which said linear contactor element is mounted; means formounting said carrier member on said support member for rotary movementabout the second preselected radius and for linear movementperpendicular to the planar surface portion of said support member;means for rotating said carrier member about the second preselectedradius to move said carrier member relative to the planar surfaceportion of said support member; and resilient means for causing linearmovement of said carrier member perpendicular to the planar surfaceportion of said support member during the rotational movement of saidcarrier member, so that said arcuate contactor element simultaneouslyand continuously rotates and slides on said linear contactor element.10. A contact making device, as recited in claim 9, in which: saidlinear contactor element is resilient and has at least one free endportion projecting from the planar surface portion of said supportmember for engagement by said arcuate contactor element.